β-amino crotonate are compounds of interest since they find use as intermediates for the synthesis of Ca channel blockers such as Nisoladipine, Benidipine, Nicardipine and such type of compounds, in the preparation and purification of various metals and as a catalyst for polymerization.
Several batch synthesis processes are disclosed in patent and non patent literature or such types of compounds.
U.S. Pat. No. 4,046,803 titled “Method Of Preparing β-Amino Derivatives Of α, β-Unsaturated Esters” discloses a method for the preparation of β-amino derivatives of α, β-unsaturated esters of the formula CH3C(NH2)═CHCOOR′ where R′ is C1 to C10 linear or branched alkyl or substituted C1 to C10 linear or branched alkyl. A reaction mixture of an acetoacetate ester of the formula CH3C(O)CH2C(O)OR′ wherein R′ is the same as defined above is first formed in an organic solvent and this mixture reacted with aqueous ammonium hydroxide in the presence of a salt of ammonia or of a metal selected from the group consisting of lithium, zinc, cadmium, cerium and lead. The salt is soluble in the organic solvent to an extent sufficient to catalyze the reaction between ammonia and the ester. The reaction product is readily recovered simply by extracting the solution with a solvent that dissolves the 8-amino a,8-unsaturated ester. But this process definitely requires the addition of a salt of ammonia or a metal in spite of addition of aqueous ammonium hydroxide, such that salt is soluble in the organic solvent to an extent sufficient to catalyze the reaction between ammonia and the ester.
U.S. Pat. No. 4,448,964 titled “1,4-Dihydropyridine derivatives” uses a process for preparation of 1,4-Dihydropyridine derivatives described in B. Loev, et al, J. Medicinal Chern., 17, 956 (1974) in Process No. 2 which is reproduce as follows:

The yield in the process is between 20-50%.
But there is no prior art disclosing a continuous flow synthesis process of β-amino crotonates. Further, there are no prior arts that disclose processes that afford high yield of beta amino crotonates.
To fulfill this gap in the art, the inventors disclose a continuous flow synthesis, process for β-amino crotonates.
Further, the invention includes a solvent free catalytic process for the synthesis of β-amino crotonate resulting in pure β-amino crotonate.